In a known technique for mounting an electronic component on a surface of a substrate, solder paste is applied onto the surface of the substrate by screen printing. Such screen printing is employed to apply metallic paste for forming inner electrodes of multilayer capacitors or multilayer inductors. In the screen printing, a screen printing stencil, such as a screen printing plate or a metallic mask, is disposed so as to overlie a recording medium such as a substrate, printing paste, such as solder paste or metallic plate, is then applied onto a surface of a squeegee with a scraper, and then the squeegee is moved so as to press the applied printing paste, so that the paste passes through multiple print pattern openings formed in the stencil and transferred to the recording medium. The screen printing stencil is required to have characteristics such as reduced bleeding of printing paste, smooth plate separation, and an enhanced paste-releasing property. Use of paste having high viscosity particularly demands smooth plate separation and an enhanced paste-releasing property.
In order to reduce the bleeding of printing paste and enhance plate separation and a paste-releasing property, for example, a metallic mask has been disclosed. In each of techniques proposed in Patent Literatures 1 to 3, an amorphous carbon film of, for example, diamond-like carbon (DLC) is provided on a surface of a screen printing mask or a print pattern opening to reduce the bleeding of printing paste and enhance plate separation and a paste-releasing property. Unfortunately, since the amorphous carbon film does not have an oil-repellent property and rather exhibits high affinity to a resin binder contained in paste, simply using the amorphous carbon film cannot reduce the bleeding of the paste and sufficiently enhance plate separation and a paste-releasing property.
Then, another technique has been studied, in which a DLC film is coated with fluorine. For instance, in Patent Literature 4, a DLC film is formed on a surface of the body of a mask by a chemical vapor deposition (CVD) method with fluorocarbon gas to incorporate a lubricant, such as fluorine resin, into the DLC film, so that a paste-releasing property can be enhanced and the bleeding of paste on a surface of a recording medium can be prevented.
Another technique has been also proposed, in which a fluorine-containing water-oil-repellent layer is formed on a surface of a DLC film without use of fluorine-containing gas. For instance, in a technique disclosed in Patent Literature 5, a surface treatment agent composed of highly stable perfluoroalkyl radical being an active ingredient is applied onto a surface of a DLC film formed on each surface of various solid substances, and then fluorine coating is further provided on the surface treating agent.